Device for measuring an imaging property of an optical system

Abstract

A device for measuring the MTF or another imaging property of an optical system has a light pattern generating unit that generates a light pattern in a focal plane of the optical system. A reference axis of the device is oriented along an optical axis of the optical system. The device further comprises an arrangement of N, N=2, 3, 4, . . . , cameras that are separated from one another. Each camera has an objective and a light sensor that is arranged in a focal plane of the objective. The cameras are arranged on a side opposite the light pattern generating unit such that the light sensor of each camera detects an image of exactly one section of the light pattern. At least one beam deflecting element is arranged between the optical system and at least one of the cameras such that it deflects light away from the reference axis before the light impinges on the at least one camera.

The invention claimed is: 
     
       1. A device for measuring an imaging property of an optical system having a focal plane and an optical axis, the device comprising:
 a) a light pattern generating unit configured to generate a light pattern in the focal plane of the optical system; 
 b) a reference axis configured to be oriented along the optical axis of the optical system; 
 c) an arrangement of N cameras, which are separated from one another, wherein N=2 or more, wherein
 each camera has an objective and a light sensor arranged in a focal plane of the objective, and 
 the cameras are arranged on a side opposite the light pattern generating unit such that the light sensor of each camera detects an image of exactly one section of the light pattern, the image being produced with the contribution of the optical system; and 
 
 d) at least one beam deflecting element, which is arranged between the optical system and at least one of the cameras such that the at least one beam deflecting element deflects light away from the reference axis before the light impinges on the at least one camera. 
 
     
     
       2. The device of  claim 1 , wherein an optical axis of at least one camera is arranged perpendicular to the reference axis. 
     
     
       3. The device of  claim 1 , wherein N>4 and wherein the cameras include at least four first cameras that are arranged in a first plane. 
     
     
       4. The device of  claim 3 , wherein the at least one beam deflecting element comprises a plurality of beam deflecting elements, and
 wherein cameras arranged in a common plane and the plurality of beam deflecting elements associated with those cameras are attached to a common support structure. 
 
     
     
       5. The device of  claim 4 , wherein the support structure has a ring-shaped mounting plate. 
     
     
       6. The device of  claim 3 , wherein N>9 and wherein the cameras include at least four second cameras that are arranged in a second plane extending parallel to the first plane. 
     
     
       7. The device of  claim 6 , wherein the at least one beam deflecting element comprises a plurality of beam deflecting elements, and
 wherein the plurality of beam deflecting elements deflect light incident on the at least four first cameras less than light incident on the at least four second cameras. 
 
     
     
       8. The device of  claim 7 , wherein the at least four first cameras and the at least four second cameras and the plurality of beam deflecting elements are arranged such that light, which exits the optical system at an angle α1 with respect to the reference axis, is deflected more strongly by the plurality of beam deflecting elements and directed at the at least four first cameras, and wherein light, which exits the optical system at an angle α2>α1 with respect to the reference axis, is deflected less strongly and directed at the at least four second cameras, and wherein the first plane is arranged farther away from the optical system than the second plane.